A std::pair is an ordered, heterogeneous sequence of exactly two objects (it is a special case of std::tuple).
std::pair is a part of the C++ Standard Library, defined in the header <utility>.
Questions tagged [std-pair]
776 questions
0
votes
1 answer
modifying vector at same iterator
Suppose i have the following vector:
std::vector > myV;
std::vector >::iterator it;
And then i initialize them for 10 row:
for (i = 0 ; i < 10; i++){
if (i % 2 == 0 )
j =…
PersianGulf
- 2,845
- 6
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- 67
0
votes
2 answers
How do I declare a constant pair inside my header file
#include
class C {
private:
const std::pair corner1(1,1);
};
GCC reports error: expected identifier before numeric constant.
I need to construct the object on the moment of it's declaration since it's const, but I can't…
Patrick.SE
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- 5
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-1
votes
0 answers
How to fix binary operator error C2678 for std::pair of both custom typedef struct Vec2 as a key value in std::map?
I have this code:
std::pair vert_pair;
vert_pair.first = vp2; // vp2 is Vec2 type
vert_pair.second = vp1; // vp1 is Vec2 type
std::map, void*> test;
test[vert_pair]; // Error C2678 when compiling
For example I…
skrovno_CZ
- 35
- 5
-1
votes
3 answers
Pair files using Python
I have a folder with several .tif files that I would like to pair to perform some functions inside a for loop.
For example:
smp001_GFP.tif
smp001_mCherry.tif
(this should be a pair)
smp002_GFP.tif
smp002_mCherry.tif
(this another pair)
I would like…
Claudia Salat
- 19
- 4
-1
votes
2 answers
How can I check, straight away, if a set of pairs have a commom number?
Suppose we have 4 pairs, e.g.:
pair P1(1, 2);
pair P2(3, 1);
pair P3(2, 1);
pair P4(1, 5);
How can I compare those 4 pairs straight away and conclude that they all have the number 1 in common? I can only…
-1
votes
1 answer
ERROR: begin was not declared in this scope for(auto x:a)
pair getMinMax(long long a[], int n) {
pair p;
p.first=a[0]; // min
p.second=a[0]; //max
for(auto x:a)
// for(int i=0; i
Srajan Gupta
- 1
- 1
-1
votes
2 answers
Having a set of regex and a set of functions, how to link each regex to a specific function and then call that function once you have a match?
// vector of pairs
vector> patterns;
// store a regex pattern
patterns[0].first = pattern;
// store a function name
patterns[0].second = func1;
patterns[1].first = pattern2;
patterns[1].second = func2;
// take…
Ammarios
- 19
- 6
-1
votes
4 answers
Finding the lower bound of vector of pairs based on first value of pair
I have a vector of pair "v" which is sorted according to the first value of the pair. Now I want to find out the lower bound of vector "v" according to the first value of the pair -- while finding the lower bound I want to ignore the second.
int pl;…
-1
votes
1 answer
Why is pair not working with unordered_map?
The following code doesn't compile.
The line with pair is giving the error. Is there some other way to access the data or is this
way correct??
unordered_map hm;
unordered_map::iterator it;
it=find(hm.begin(),hm.end(),x+c);
if…
Kshitij Tripathi
- 13
- 1
-1
votes
1 answer
inserting a double and a pair in map and printing the map
I want to build a container for fractions. The key will represent the value of the fraction in double; The numerator and the denominator are stored in a pair.
std::map> m ();
I had problems with inserting and printing…
Simona
- 53
- 1
- 12
-1
votes
3 answers
How can I fix the missing template arguments before '(' token problem here?
I am getting the problem on line 15 and 20 where i am trying to pushback elements in to the pair vector
#include
#include
#include
using namespace std;
int main()
{
int x, y, a, b, c, d, j, m, v;
…
user13869329
-1
votes
1 answer
Unable to find the corner case I'm missing in a question I recently encountered
In yesterday's CodeChef contest I came across this problem in which I was able to write the code which was able to solve all the "normal" testcases, however, it failed when it came to a probable corner case that I seem to have missed.
The question…
AyushGupta
- 11
- 2
-1
votes
1 answer
How to use numeric library function with a vector of pairs?
I am trying to use the function adjacent_difference from the numeric library on the second element of each entry of a vector of pairs (vector>). How can I do it?
Update: here's my code so far (obviously wrong xD):
vector…
Mike Robertson
- 21
- 2
-1
votes
1 answer
making second argument of std::pair a custom class
I am implementing a Node class in C++ as an assignment.
The class :
#pragma once
#include
class Node {
size_t id;
std::pair dist;
public:
//Node();
//Node(const size_t);
Node(const size_t, const…
kesarling He-Him
- 1,944
- 3
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- 39
-1
votes
1 answer
My C++ program is not working ...just got stuck in this dont know what to do
I wanted to take the values from user and wanted to sort it... so i took values in two arrays one in string array and the other in int array... if i sort the string array it get sorted very well.. i m not able to sort the int array accordingly....…
Pankaj Mohan
- 21